Re: Error -1811

Andrew Hardy wrote: > Though I am sure it ought to be obvious to me, I think may be I am > misunderstanding the term 'DATABASE statements' what to you mean, In this context, a 'DATABASE statement' means, precisely, an SQL statement that includes the keyword DATABASE: DATABASE 'xyz; CLOSE DATABASE; CREATE DATABASE 'xyz'; DROP DATABASE 'xyz'; ROLLFORWARD DATABASE 'xyz'; -- SE only START DATABASE 'xyz' ....; -- SE only I think that's complete, which means I've probably forgotten a couple. The term 'DATABASE statement' explicitly excludes any SQL statement that is not in the list above (assuming that list is complete) - it does not include SELECT, INSERT, DELETE, UPDATE, CREATE <anything-but-database>, DROP <anything-but-database>, and so on. > cannot I not do: > > CONNECT TO ... > > then do > > EXEC SQL etc etc Of course, as long as 'etc etc' does not include one of the DATABASE statements. > I don't understand why not. > > Also what do you specifically mean by > > 'the CONNECT statement' > > Does this mean any kind of CONNECT. I'm referring to EXEC SQL CONNECT TO ... in all its forms. > I am using CONNECT TO ... AS ..., > then from time to time I use SET CONNECTION > to as I understand change the current connection. There's no problem there. How you create the connection controls what you can do; once you've got several connections, you can switch among them as you see fit. What is critical is that you can have an ESQL/C program with no CONNECT statement; for example, one that reads: int main(void) { EXEC SQL WHENEVER ERROR STOP; EXEC SQL DATABASE 'xyz'; EXEC SQL CREATE TEMP TABLE t93(i INT NOT NULL); ... return(0); } This creates an implicit connection to the database server - the DATABASE statement creates an implicit connection. But, this program could do things like 'EXEC SQL DROP DATABASE "pqr";' using that connection, whereas if you wrote an explicit 'EXEC SQL CONNECT TO "xyz";', the program would be unable to drop another database. > A lot of the code is wrapped, so it's difficult to get to the boittom of None of the code I sent was wrapped, AFAICS. > it, but I think some of the scenarios is: > > CONNECT TO ... AS > > EXEC ... > EXEC ... > EXEC ... > > CONNECT TO ... AS > > get error -1811 No. > =================================== > > CONNECT TO ... AS b > > EXEC ... > EXEC ... > EXEC ... > > SET CONNECTION TO c (some other previous connection) > > EXEC ... > no error > > ======================================= > > CONNECT TO ... AS b > > EXEC ... > EXEC ... > EXEC ... > > SET CONNECTION TO c (some other previous connection) > SET CONNECTION TO c ... DORMANT > > EXEC ... > error -1811 I don't think you get -1811 if you attempt to use a dormant connection, but I'd stand to be corrected. > ======================================== > > CONNECT TO ... AS b > > EXEC ... > > begin > EXEC ... > EXEC ... > > SET CONNECTION TO c (some other previous connection) This will fail unless you added WITH CONCURRENT TRANSACTIONS to the original CONNECT statement. > SET CONNECTION TO c ... DORMANT > > SET CONNECTION TO b > EXEC ... > EXEC ... > end > error -1811 Assuming you had the correct connection, then this would not be an error. > ...Posting by Jonathan Leffler... > Andrew Hardy wrote: > >>can somebody explain to me what this means: >> >>lesu273> finderr -1811 >>-1811 Implicit connection not allowed after an explicit connection. >> >>Once you have used the CONNECT TO statement to establish an explicit >>connection to a database server, you cannot use one of the DATABASE >>statements to connect implicitly to another database server. After an >>explicit connection, you must use the CONNECT TO statement to connect >>to other database servers. >> >> >>If I have established an explicit connection to a db server, then surely >>any using one of the databse statements after tha, must be asumed to be >>sent to that server ? > > > Yes, but did you connect to the server or to a specific database on > the server? > > You can create an implicit connection like this: > DATABASE 'joe@bloggs'; > You can also create an implicit connection like this: > DATABASE 'joe'; > > You can create an explicit connection to a database like this: > CONNECT TO 'joe@bloggs'; > After this, you cannot use any of the DATABASE statements. > > You can create an explicit connection to a database server like this: > CONNECT TO '@bloggs'; > And after this, you can do: > CREATE DATABASE bill;> CLOSE DATABASE; > DATABASE joe;> ... > CLOSE DATABASE; > > And so on. > >>So why does the statement I execute think it is for a different server? > > The error message is clear - you are not allowed to create an implicit > connection after you've made an explicit connection to a database. > > The expansion of the error message is not as clear as it could be. > Better wording would be more like: > > Once you use the CONNECT statement to establish an explicit connection > to a database, you cannot use any of the DATABASE statements when that > is the current connection. You can use the notation CONNECT TO > 'dbase@server' to connect to a different database, or the notation > CONNECT TO '@server' to connect to a database server (after which, you > can use the various DATABASE statements in that connection). -- Jonathan Leffler #include <disclaimer.h> Email: jleffler@earthlink.net, jleffler@us.ibm.com Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/